[PATCH V2 1/7] clockevents: Allow set-state callbacks to be optional

Viresh Kumar
2015-06-12T08:00:41Z

Its mandatory for the drivers to provide set_state_{oneshot|periodic}()
(only if related modes are supported) and set_state_shutdown() callbacks
today, if they are implementing the new set-state interface.

But this leads to unnecessary noop callbacks for drivers which don't
want to implement them. Over that, it will lead to a full function call
for nothing really useful.

Lets make all set-state callbacks optional.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
kernel/time/clockevents.c | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 2397b97320d8..37ba06f01818 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -120,19 +120,25 @@ static int __clockevents_switch_state(struct clock_event_device *dev,
/* The clockevent device is getting replaced. Shut it down. */

case CLOCK_EVT_STATE_SHUTDOWN:
- return dev->set_state_shutdown(dev);
+ if (dev->set_state_shutdown)
+ return dev->set_state_shutdown(dev);
+ return 0;

case CLOCK_EVT_STATE_PERIODIC:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_PERIODIC))
return -ENOSYS;
- return dev->set_state_periodic(dev);
+ if (dev->set_state_periodic)
+ return dev->set_state_periodic(dev);
+ return 0;

case CLOCK_EVT_STATE_ONESHOT:
/* Core internal bug */
if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
return -ENOSYS;
- return dev->set_state_oneshot(dev);
+ if (dev->set_state_oneshot)
+ return dev->set_state_oneshot(dev);
+ return 0;

case CLOCK_EVT_STATE_ONESHOT_STOPPED:
/* Core internal bug */
@@ -471,18 +477,6 @@ static int clockevents_sanity_check(struct clock_event_device *dev)
if (dev->features & CLOCK_EVT_FEAT_DUMMY)
return 0;

- /* New state-specific callbacks */
- if (!dev->set_state_shutdown)
- return -EINVAL;
-
- if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
- !dev->set_state_periodic)
- return -EINVAL;
-
- if ((dev->features & CLOCK_EVT_FEAT_ONESHOT) &&
- !dev->set_state_oneshot)
- return -EINVAL;
-
return 0;
}

--
2.4.0